1. The Field of Invention
The present invention relates generally to a combination blade assembly that is attached to the blade shaft of a riding type power lawn mower to modify the mower for mulching and chipping. More specifically, the present invention relates to a combination blade assembly which modifies the riding type power lawn mower to be used for mulching and chipping of branches, brush and tough organic materials in addition to the grass cutting capabilities of the mower, without repeated conversion of the mower after the initial installation of the combination blade assembly on the mower.
2. History of Prior Art
The present prior art provides devices designed primarily for relatively lightweight use in a home garden of soft refuse, yet at the same time provides an efficient shredding and mulching machine enabling such refuse to be chopped finely enough to be incorporated back into the garden if desired, and is also readily converted for use as a lawn mower when desired.
It is often desirable that a riding type power lawn mower is capable of not only cutting grass, leaves and lightweight organic matter, but also possess mulching and chipping capabilities for heavy-weight branches, brush and tough organic materials.
Patents reviewed have disclosed several devices for mulching and chipping organic matter. Many such devices are free standing mulchers and chippers, while other devices are designed to be used with or to modify rotary type power lawn mowers.
The Bendig U.S. Pat. No. 4,796,416, shows a mulching attachment having an upper blade with a spacer coupled to a lower blade and base plate. This blade assembly is used with a rotary type power lawn mower for mulching light-weight organic matter. However, the Bendig patent requires extensive disassemblage of the mower when it is desirable to attach the blade assembly for the conversion of the mower to a mulcher. This conversion prohibits the mower to be used consecutively for cutting grass. Additionally, the Bendig patent requires partial removal of the blade assembly from the mower when it is desirable to use the mower for cutting grass. The required conversion of the mower to a mulcher and back to a mower is time consuming and too laborious for the operator.
The Leuz U.S. Pat. No. 4,901,509, shows a funnel-shaped chute attachment for a rotary type power lawn mower. The device converts the mower to a garden mulcher. This conversion does not allow the mower to be used consecutively for cutting grass. The funnel-shaped attachment must first be removed from the mower, and a coverplate placed over the opening in the mower deck and further disassembling of the mower blade and reassembling of the blade when it is desirable to use the mower for cutting grass. Additionally the Leuz patent was designed specifically for modifying a rotary type power lawn mower to a mulcher of light-weight garden materials.
The Brokaw U.S. Pat. No. 4,057,952, shows a rotary type power lawn mower with chipping and mulching capabilities due to a set of three blades attached to a vertical drive shaft. The three blades include a top chopping blade, a middle shredder blade, and bottom mower blade. The chipping blade is described as being much heavier than the mower blade and acts as a fly wheel to provide increased cutting energy as compared to the horse power of the mower. However, the Brokaw patent assemblage involves a number of parts making the adaption cost prohibitive and too difficult for the average mower owner to assemble. A bottom plate is secured to the mower while being used as a mulcher, this bottom plate prohibits the mower from being used consecutively for cutting grass. The Brokaw patent is also susceptible for organic materials to become lodged in the chopping assembly of the feed roller, as well as the chopping blades. Additionally, due to the complex design, the blade assembly is not suitable for utilization with a riding type power lawn mower.
The Haas U.S. Pat. No. 4,083,166, shows a mulcher attachment comprised of a lightweight circular disc blade with a plurality of openings and blade portions for use with a rotary type power lawn mower that shreds and mulches the lightweight organic materials produced during operation of the mower. However, due to the upward suction of organic materials through the openings of the circular disc blade, the Haas patent is not capable of mulching or shredding large, heavy-weight materials. Whatever the precise merits, features and advantages of the above cited references, none of them achieves or fulfils the purposes of a combination blade assembly as accomplished by the present invention.